This invention relates generally to a vehicle main frame having a pair of arms, and more particularly to a main frame for more effectively transmitting forces from an implement through the arms thereof.
In general, many vehicles such as a track-type tractors or the like have a pair of parallel arms, a saddle connected between the arms, and an equalizer bar pivotally mounted to the saddle. The ends of the equalizer bar are in turn seated on an opposite pair of vehicle undercarriages or track roller frames pivotally secured to the body of the tractor.
In the past, however, implements such as a C-frame mounted bulldozer blade have been pivotally mounted to the outside of such oscillating frames roller frame because of several problems that develop when any attempt is made to mount them on the inside thereof. For example, only a minimum of lateral clearance exists between the main frame arms and the track roller frames to that for the most part previous inside mounted C-frames have been limited to those tractors having non-oscillating track roller frames. Unfortunately, there are many disadvantages to such fixed undercarriages including poorer vehicle maneuverability over irregular terrain and loss of traction under adverse footing conditions.
Another problem with inside mounted C-frames, is that they have been heretofore connected to the main frame arms on outstanding pins in such a manner that they have imposed undesirable twisting loads and fatigue stresses on the main frame arms. Accordingly, these arms have been made more rigid and costly in construction in order to withstand the high forces of the bulldozer blade. Another disadvantage is that these heavier arms are often deeper in cross section, which imposes servicing problems because certain components of the tractor are then not conveniently accessible. Furthermore, these C-frames have been coupled to the main frames at elevationally low pivot axes so that there has been less ground clearance under the frames.
Therefore, it can be appreciated that it would be advantageous to provide a vehicle with a pivotal equalizer bar to allow the track roller frames to oscillate for better maneuverability and overall operation of the tractor, and also an inside mounted implement that can more effectively distribute working forces into the main frame arms and can thereby overcome the problems associated with the prior art. Also, inside mounting of the implement reduces the vehicle width to the width of the usual blade.